Superheater arrangement



March 31, 1936. E. A. ROBINSON SUPERHEATER ARRANGEMENT Filed June 6,1935 2 Sheets-Sheet 1 r I L INVENTOR E/P/c A. Roe/M50. BY Q 1 W ATTORNEYPatented Mar. 31, 1936 UNITED STATES SUPERHEATER ARRANGEMENT Eric A.Robinson, Marylebone, London, England, assignor to The superheaterCompany, New

York, N. Y.

Application June 6, 1935, Serial No. 25,266 In Great Britain October 26,1933 7 Claims.

This application relates to improvements in the steam superheatinginstallations of steam generators. It is in part a continuation ofUnited States application 748,457, filed by me on October 16, 1934.

superheating installations are known wherein the superheater as regardsits width across the boiler is divided into two sections which arearranged in parallel, and may be termed the righthand and left-handsuperheaters, and in which each of said superheaters comprises a primarysection and a final section, and it is to superheater installations ofthis character that the improvements according'to the present inventionare directed.

One object of the present invention is to provide a method of, and meansor apparatus for, compensating for the efiect on two superheatersarranged side by side across a boiler, and operating in parallel, ofdifferences in firing across the boiler, in order to avoid materialdifferences between the temperatures of the steam delivered by therespective superheaters, and, it may be, prevent excessive temperaturein the secondary or final section of either superheater.

The invention resides primarily in a method of compensating for theeffect on two steam superheaters arranged side by side across a boilerand operating in parallel, of differences in firing across the boiler,consisting in dividing each superheater into a primary section and asecondary or final section and heating the primary section of onesuperheater and the secondary or final section of the other superheaterby the products of the combustion of fuel at one side of the boiler andheating the remaining sections of the two superheaters by the productsof combustion of fuel at the other side of the boiler. Further, I havehereinbelow disclosed one form of my invention in connection with anarrangement of desuperheaters. However, I donot claim anything herein asto the manner of using desuperheaters or as to their arrangement, itbeing known to employ desuperheaters between two sections of asuperheater and the details of the desuperheater shown forming no partof my invention, being disclosed in patent to Andre Huet, No. 1,964,060,June 26, 1934.

. In addition the invention consists in apparatus for superheating steamas defined in the claims which will appear hereinafter, and as will nowbe described with reference to the accompanying drawings, in which Fig.1 shows in diagrammatic plan a steam superheating installation equippedwith temperature control means, certain of the pipes leading to and fromthe desuperheaters of the installation being omitted for simplicity ofillustration;

Fig. 2 is a diagrammatic elevation of the installation shown in Fig. l,and including the sev- 5 eral pipes omitted from that figure;

Fig. 3 is a fragmentary view showing a modification in the arrangementof certain parts, as will be described hereinafter;

Fig. 4 is a diagrammatic plan view of a modi- 1O fied arrangement of thesuperheater sections;

Fig. 5 is a lateral elevation thereof; and

Fig. 6 is a view similar to Fig. 5 showing a modification of the form ofFig. 5.

Referring to the drawings, the invention is shown therein, by way ofexample, as applied to the superheater of a water tube boiler of thesemi-vertical type, but it is to be understood that the invention may beapplied to the superheaters of boilers of other types. y

In the embodiment of the invention shown in Figs. 1 and 2, theinstallation comprises two superheaters each consisting of a primarysection and a secondary section. The primary sections comprise inletheaders I, 2, collecting headers 3, 4, and elements 5, 6, whilst thesecondary sections comprise distributing headers I, 8, outlet headers 9,l0, and elements ll, l2.

The superheater elements are distributed across the boiler, and toobtain an eflicient distribution of steam to the elements of eachsuperheater steam is fed to one end of the inlet or distributing header1 or 2, or 1 or 8 of a superheater, and is withdrawn from the oppositeend of the collecting or outlet header 3 or 4, or 9 or 10, of suchsuperheater, this method of steam distribution to superheater elementsbeing well known. The collecting header 3 or 4 of a primary superheateris connected to the distributing header 1 or 8 of a secondarysuperheater at the opposite side of the boiler, that is to say theleft-hand primary superheater supplies steam to the right-hand secondarysuperheater and the right-hand primary superheater supplies the steamfor the left-hand secondary superheater. By this arrangement ofcross-connection of the superheaters variations in firing as between thetwo sides of the boiler are compensated for, so that uneven firingacross the width of the boiler will not cause material difierence in thetemperature of the steam delivered by one secondary section as comparedwith that delivered by the other secondary section.

In Fig. 1, a steam and water drum I3 is shown, whilst in Fig. 2 thereisshown also a water drum M of the boiler. The installation shownincludes g and the other superheater and its associated parts in brokenor dotted lines.

In order to maintain the temperature 'of'the steam delivered by thesuperheater installation constant notwithstanding variation in the load,

on the boiler, and consequent variation in the firing, there isassociated with each of the crossover connections I9, 2|, 23 or 2B; 22,24, adesuperheating apparatus 25 or 26 respectively. Each desuperheateris of the non-contact type, and valve means control the proportion ofsteam which flows through the desuperheater and the'otherwise directpath from a primary to a secondary superheater. Conveniently two valves2T, 29 or 28,30, which may be of the butterfly type, are employed ineach cross-over, one valve 21 or '28 controlling the direct path betweenthe superheater sections and the other valve 29 or 30 controlling thepath through the desuperheater. These valves are controlled bythermostats 3|, 32 in the outlets I'I, I8 for superheated steam from therespective secondary sections of the superheater.

The desuperheating apparatus shown is of known construction andcomprises a drum or vessel having a lower portion constituting a hichambered header and tube plate, inverted U- loop tubes being connectedto the header portion of' the desuperheater. One header chamber isconnected to the portion I 9 or 20 of the cross-over leading from theprimary superheater and the other is connected to the portion 23' or 24leading to the secondary superheater. To the drum or vessel above thetube plate wateris supplied by a connection 33 or 34 from the bottomboiler drum I4 and the desuperheater is disposed in such a manner thatwith the water level therein coincident with the water level in the topboiler drum I3 the U-shaped heat exchange tubes in the drum aresubmerged. Below the normal water level a circulating pipe 35 or 36connects the water space of the desuperheater with the water space ofthe upper boiler drum I3. From the top of the de-' superheater aconnection 31 or 38 is provided for delivering steam generated in thedesuperheater to the steam space of the upper drum I3 of the boiler.

By arranging the desuperheater and its connections to the boiler drumsin the manner described, Water will circulate from the drum I4, throughheater will riseQdue to the'presence of steamin the body of water in thedesuperheater rendering such water less dense than the boiler water.Consequently, as shown in Fig. 3, the pipe-35B by which waterreturns tothe boiler drum I3 may By thus 2,035,763 a 1 p i z take off from thedesuperheater casing at a point above the normal water level in theboiler but below the level to which water rises in the desuperheaterwhen the latter is in operation. Thus circulation of boiler waterthrough the desuperheater will be maintained when the desuperheater isin operation, but not take place when the desuperheater is not working.

It will be appreciated that on a rise in temperature of the steamdelivered by a secondary super-heater the thermostatically controlledvalves will operate to pass a greater proportion of the steam from theassociated primary superheater through the desuperheater, and thusreduce the temperature of the steam entering the secondary section ofthe superheater, so that a reduction in 'the final steam temperature atthat secondary section of the superheater will be obtained. Thusexcessive temperature either in the secondary section of the superheateror at the prime mover will be prevented. As already indicated thecross-connection from the primary superheater at one side of the boilerto the-secondary superheater atthe other side of the boiler ensures thatthe two secondary superheaters deliver steam at the same orsubstantially the same temperature, as should the boiler be fired moreheavily on one side than on'the other the increase in the primary steamtemperature at the one side of the boiler will be. oiTset by thereduction in the'superheater in the secondary section on the other sideof the boiler, and the lower, superheat in' the other primary sectionwill be compensated forby the increased superheat in its associatedsecondary section.

- The principal difference between the forms of the inventionillustrated in Figs.4 to '6 from theform shown in Figs. 1 and 2 lies inthe fact that the superheater sections on'either'side of' the boiler arenot separated from each other in' the direction of 'gas'travel, but areat the same distance from the furnace, the tubular elements of one beinginterleaved with those of the other.

The inlet headers in these figures'are again designated by' thereferencenumerals I and Z, and the elements to which they deliver the saturatedsteam are shown at 5 and 6 respectively. The outlet ends of theseelements are connected respectively to the intermediate headers 50 and5|. It is possible with this arrangement to make the header to whicheach first section elements deliver steam continuous and unitary withthe inlet header for'the corresponding second section and this is donein the form shown, headers 50 and SI extending across the boiler settingfrom side to side and serving as outlet headers for the first sectionsand inlet headers for the second sections. H 7

The'straight tube lengths of adjacent loops may be abreast of each otherso all of them are in alinement transversely of the boiler setting as inFig. 5, or they may be staggered as in Fig. 6.

Although certain constructional details have been referred to herein theinvention is not necessarily restricted .to all the details ofconstruction describedas some variations might be made without departingfrom the invention.

What I claim is:

1. A method of compensating for the effect on two steam superheatersarranged side by side across a boiler, and operating in parallel, ofdifferences in firing across the boiler, consisting in dividing eachsuperheater 'into a primary sectionand a secondary or final section andheating the primary section of one superheater and the secondary orfinal section of the other superheater by the products of the combustionof fuel at one side of the boiler and heating the remaining sections ofthe two superheaters by the products of combustion of fuel at the otherside of the boiler.

2. A method of compensating for the effect on two steam superheatersarranged side by side across a boiler, and operating in parallel, ofdifferences in firing across the boiler, and of controlling the finaltemperature of steam delivered by such superheating installation,consisting in dividing each superheater into a primary section and asecondary or final section, delivering steam from a primary section of asuperheater into its associated secondary or final section eitherdirectly or through a desuperheater individual to such superheater,heating the primary section of one superheater and the secondary orfinal section of the other superheater by the products of the combustionof fuel at one side of the boiler, heating the remaining sections of thetwo superheaters by the products of combustion of fuel at the other sideof the boiler, and regulating automatically in each superheater theproportions of steam flowing through the direct path and desuperheater,respectively, by thermostatically controlled means responsive tovariations in the temperature of the steam delivered by the finalsection of such superheater.

3. A steam superheating installation comprising two superheatersarranged side by side across a boiler and operating in parallel, eachsuperheater having a primary section and. a secondary or final sectionconnected in series, wherein the secondary or final section of each ofthe pair of superheaters is disposed at the side of the boiler oppositeto that at which its associated primary section is located, for thepurpose set forth.

4.-A steam superheating installation according to claim 3, the secondarysections being at a'difierent distance from the furnace as regards gasfi'ow than the two primary sections.

5. A steam superheating installation according to claim 3, the secondarysections being more remote from the furnace as regards gas flow than thetwo primary sections.

6. A steam superheating installation according to claim 3, the secondaryand the primary sections all being at substantially the same distancefrom the furnace as regards gas flow.

'7. A steam superheating installation according to claim 3, thesecondary and the primary sections all being at substantially the samedistance from the furnace as regards gas flow, the elements of eachprimary section alternating with those of the secondary section of theother superheater.

ERIC A. ROBINSON.

